Renal artery stenosis

Disease Description (Causes and Symptoms)

• Definition: Renal artery stenosis is a condition in which the renal arteries that supply blood from the aorta to the kidneys become narrowed, reducing blood flow to the kidneys.
• Main causes
  • Middle-aged and older adults: Atherosclerosis is the most common cause (risk factors include smoking, advanced age, diabetes, and hyperlipidemia).
  • Younger adults (especially women): Fibromuscular dysplasia (FMD).
• Pathophysiology summary: Reduced renal perfusion → increased renin secretion by the kidneys → activation of the renin–angiotensin–aldosterone system → secondary hypertension and fluid and electrolyte changes. Long-term reduction in perfusion may cause declining kidney function and kidney atrophy.
• Main symptoms: Hypertension (especially unusually early-onset or resistant hypertension), decreased urine output, fatigue, loss of appetite, nausea, anemia, symptoms of kidney failure, shortness of breath during exercise, seizures, etc.

Treatment (Standard Treatment, Medications, Procedures/Surgery, Lifestyle Management and Precautions)

• Medication treatment
  • Blood pressure control: Calcium channel blockers, beta-blockers, diuretics, etc. may be used.
  • Precautions when using ACE inhibitors (e.g., captopril) or ARBs: In cases of severe bilateral renal artery stenosis or a solitary kidney, these drugs may cause acute worsening of kidney function, so kidney function (creatinine) and electrolytes must be monitored before and after use.
  • If the cause is atherosclerotic, statins and antiplatelet agents may be considered for cardiovascular risk management.
• Revascularization treatment
  • Percutaneous transluminal angioplasty (PTA; balloon angioplasty) ± stent: Particularly effective for fibromuscular dysplasia (hypertension may be cured in some patients). Stenting is commonly performed for atherosclerotic lesions.
  • Surgical revascularization (such as bypass surgery): Considered when anatomically appropriate or when a procedure has failed or is unsuitable.
• Management before and after procedures
  • Before the procedure, check kidney function and urine output, and take measures to prevent contrast-induced nephrotoxicity, such as fluid replacement, when contrast media are used.
  • After the procedure, prevention of stent thrombosis and blood pressure monitoring are necessary.
• Lifestyle management and prevention
  • Manage cardiovascular risk factors through smoking cessation, blood glucose and lipid control, weight management, regular exercise, and a low-sodium diet.
• Precautions and risk of complications
  • If left untreated, uncontrolled hypertension increases the risk of cardiovascular complications, including stroke, coronary artery disease, heart failure, and retinopathy.
  • Revascularization may involve bleeding, vascular injury, contrast-induced kidney injury, and possible restenosis of the stent.
  • Kidney function may worsen when using ACE inhibitors/ARBs—kidney function and potassium must be monitored when starting or increasing the dose.

Checklist Before an Outpatient Visit (Items to Prepare and Information to Confirm, Including Example Questions)

• Items to prepare and materials that can be submitted
  • A list of all medications currently being taken, including directions and dosage; recently used prescriptions or medication bottles
  • Previous test results (blood tests—creatinine, electrolytes, lipids, and blood glucose; urinalysis), and previous imaging materials (abdominal CT, ultrasound, renal angiography, etc.)—the originals or a CD, if possible
  • Blood pressure records (home and hospital blood pressure), and notes on when symptoms began and how they have progressed (changes in urine output, fatigue, falls or syncope, etc.)
  • Allergies (especially contrast media allergies) and whether there is any possibility of pregnancy
• Items recorded and measured during the outpatient visit
  • Current blood pressure and heart rate, weight, changes in urine output, and kidney function (recent test results)
• Information that is useful to show the doctor before the outpatient visit
  • Age at onset of hypertension, whether it is controlled with medication (if it is resistant, which medications have been taken and for how long), and coexisting conditions (diabetes, hyperlipidemia, and cardiovascular disease)

Examples of General Questions to Ask the Doctor

• What are the common side effects of this medication (the antihypertensive I am currently taking)?
• How often should my kidney function (or creatinine level) be tested?
• Are there any lifestyle factors I should specifically avoid or changes that are recommended?
• What are the advantages and disadvantages of revascularization (balloon angioplasty/stenting), and what is the likelihood of success?
• What is the risk of recurrence (restenosis), and what is the follow-up testing plan?

Examples of Condition-Specific Questions

• Considering my case (age, imaging findings, and underlying conditions), is a procedure (angioplasty/stenting) recommended, or should it first be managed with medication?
• If I use an ACE inhibitor/ARB, is there a risk that my kidney function will worsen? What tests and monitoring are needed if I use it?

(Organizing the above questions by priority before your appointment can make the consultation more efficient.)